This contribution summarizes the use of plasmon surface polaritons and
guided optical waves for the characterization of interfaces and thin
organic films. After a short introduction to the theoretical backgroun
d of evanescent wave optics, examples are given that show how this int
erfacial ''light'' can be employed to monitor thin coatings at a solid
/air or solid/liquid interface. Examples are given for a very sensitiv
e thickness determination of samples ranging from self-assembled monol
ayers, to multilayer assemblies prepared by the Langmuir/Blodgett/Kuhn
technique or by the alternate polyelectrolyte deposition. These are c
omplemented by the demonstration of the potential of the technique to
also monitor time-dependent processes in a kinetic mode. Here, we put
an emphasis on the combination set-up of surface plasmon optics with e
lectrochemical techniques, allowing for the online characterization of
various surface functionalization strategies, e.g. for (bio-) sensor
purposes.